Just adding to the conversation, I’ve noticed that drought stress also contributes greatly to PM susceptibility in cannabis. Drying back too deep, like to the point of drooping, does something that allows the PM to flourish.
Thanks for commenting. At this point you're also heavily increasing stress on the plant, which makes it vulnerable to a variety of diseases, including PM. Over drying is never positive for plant defenses.
Thank you for your great videos, I always learn a lot from them !! I've heard of heat also working great to kill PM. If I remember correctly, it was a Spanish studie that shows that 38°C for 6 hours pretty much destroy it all.
It’s not quite as simple as this. I’ve tried it several times and it did not harm my plants but certainly did not cure the PM. There is apparently more to the story. Not to mention, PM is not one organism, there are many kinds.
PM(and most fungal diseases) likes a few things: low pH, high oxidation, deficiency in both potassium and calcium but with calcium even lower, deficiency in boron and deficiency in silica. Skimming your video, it looks like a lot of the solutions are raising the pH, but also raising the oxidation. I don't know of a foliar where you can both increase pH and reduce oxidation. But you can increase pH and reduce oxidation in the substrate with good nutrient management.
Thanks for commenting. I don't know exactly what you refer to by "raising oxidation", many of these sprays have no oxidants present (like for example plain vegetable oils).
If any of our crops are nutrient deficient, it’s pointless to be worrying about mildew. Most of us growing hydroponically are giving the plants an unlimited supply of nutrients.
Thanks for your reply. No, sulfur to control PM needs to be in the form of elemental sulfur. Sulfate, the sulfur form present in magnesium sulfate and other such salts, does not work for this purpose.
Excellent!!! Does it also work the same for DM (Downy Mildew)? If not, could you please do something similar for DM? Its monsoon time here in India and the season of Mildews is going to be soon on us.
Thanks for commenting. These solutions don't work well for Downy Mildew. Sadly this is a more complicated disease. Phosphorous acid applications (not phosphoric!) are usually highly effective against downy mildew, you can search for publications about this to learn more (maybe I'll make a future video about it.
Hello Daniel,I am a european fellow of yours,what values do you suggest in my formulation including average 50ppm of calcium and 27 of Magnesium and a Total alkalinity of 220ppm Carbonates of my tap water,considering It Is for Coco coir Hydroponic cultivars? I have problems with Coco coir specifico formulation fertilizers and calcium uptake/lockout
Thanks for commenting! Checkout my video on a one part formulation for very hard water (scienceinhydroponics.com/2022/06/a-one-part-hydroponic-nutrient-formulation-for-very-hard-water.html).
I grow in Los Angeles California where the water is hard and alkaline, with total alkalinity of 80-120, calcium 40-70ppm, magnesium 8-30ppm. I have great success growing in coco using nutrients designed for use with RO water. These nutrients come with all the Ca/Mg needed for healthy plants, so the amount of water is extra. The nutrient I use for vegetative growth for cannabis and vegetables is Jacks 12-4-16 at 5.5g/gal + 0.87g/gal epsom salts, ph corrected with phosphoric acid to 5.5. If you can get a nutrient breakdown for that product and find something similar in your area I suggest giving it a shot. I plant clones into straight coir and feed them at the rate I mentioned from when they are babies all the way to when they are ready to move into the production environment. You must water to runoff every 3 or 4 irrigations or else you risk getting a toxic buildup, as most hydroponic nutrients are not designed for nutrient retention like nutrients designed for natural soil. For blooming cannabis, I switch to Athena Bloom + Core at 8g/gal and 5g/gal respectively, ph adjusted to a stable 5.8 (mixing to a ph of 5.5 in this case will settle to 5.8 after 12 hours of aeration in the reservoir). I've noticed that municipal water ph drifts quite a bit several hours after mixing so you must create a batch of nutrient and check it the next day or else use a device to correct the ph as it drifts before giving it to the plants. Again, you could look up people's published nutrient breakdowns of this nutrient to see how it compares with products in your area, or custom mixes. In my opinion, what people usually attribute to calcium lockout with coir is usually really a ph issue, low quality coir with an extremely high initial potassium content, or over irrigation (constantly soggy root conditions). All of my suggestions above are with artificial lighting with relatively high intensity and co2 enrichment; if you are growing under natural lighting I would adjust the nutrients down.
Just adding to the conversation, I’ve noticed that drought stress also contributes greatly to PM susceptibility in cannabis. Drying back too deep, like to the point of drooping, does something that allows the PM to flourish.
Thanks for commenting. At this point you're also heavily increasing stress on the plant, which makes it vulnerable to a variety of diseases, including PM. Over drying is never positive for plant defenses.
Thank you for your great videos, I always learn a lot from them !! I've heard of heat also working great to kill PM. If I remember correctly, it was a Spanish studie that shows that 38°C for 6 hours pretty much destroy it all.
Thanks for commenting! 38C is pretty high!
It’s not quite as simple as this. I’ve tried it several times and it did not harm my plants but certainly did not cure the PM. There is apparently more to the story. Not to mention, PM is not one organism, there are many kinds.
PM(and most fungal diseases) likes a few things: low pH, high oxidation, deficiency in both potassium and calcium but with calcium even lower, deficiency in boron and deficiency in silica.
Skimming your video, it looks like a lot of the solutions are raising the pH, but also raising the oxidation. I don't know of a foliar where you can both increase pH and reduce oxidation. But you can increase pH and reduce oxidation in the substrate with good nutrient management.
Thanks for commenting. I don't know exactly what you refer to by "raising oxidation", many of these sprays have no oxidants present (like for example plain vegetable oils).
If any of our crops are nutrient deficient, it’s pointless to be worrying about mildew. Most of us growing hydroponically are giving the plants an unlimited supply of nutrients.
What concentration of vegitabke oil should I spray on my plants?
Keep in mind that vegetable oils will harden or get sticky. Mineral oils remain washable with regular soap even after months being left on surfaces.
Thanks for commenting. This is certainly a consideration to make, the vegetable oils do degrade and their degradation products are indeed more sticky.
Can you make a video where you showing us how to use properly ppm calculator? And everything in it
Please watch my video on electrical conductivity for more information about EC/ppm.
Can i use epsom salt diluited in water as sulfur source via foliar feed to combat PM?
Thanks for your reply. No, sulfur to control PM needs to be in the form of elemental sulfur. Sulfate, the sulfur form present in magnesium sulfate and other such salts, does not work for this purpose.
Excellent!!! Does it also work the same for DM (Downy Mildew)? If not, could you please do something similar for DM? Its monsoon time here in India and the season of Mildews is going to be soon on us.
Thanks for commenting. These solutions don't work well for Downy Mildew. Sadly this is a more complicated disease. Phosphorous acid applications (not phosphoric!) are usually highly effective against downy mildew, you can search for publications about this to learn more (maybe I'll make a future video about it.
Hello Daniel,I am a european fellow of yours,what values do you suggest in my formulation including average 50ppm of calcium and 27 of Magnesium and a Total alkalinity of 220ppm Carbonates of my tap water,considering It Is for Coco coir Hydroponic cultivars?
I have problems with Coco coir specifico formulation fertilizers and calcium uptake/lockout
Thanks for commenting! Checkout my video on a one part formulation for very hard water (scienceinhydroponics.com/2022/06/a-one-part-hydroponic-nutrient-formulation-for-very-hard-water.html).
I grow in Los Angeles California where the water is hard and alkaline, with total alkalinity of 80-120, calcium 40-70ppm, magnesium 8-30ppm. I have great success growing in coco using nutrients designed for use with RO water. These nutrients come with all the Ca/Mg needed for healthy plants, so the amount of water is extra. The nutrient I use for vegetative growth for cannabis and vegetables is Jacks 12-4-16 at 5.5g/gal + 0.87g/gal epsom salts, ph corrected with phosphoric acid to 5.5. If you can get a nutrient breakdown for that product and find something similar in your area I suggest giving it a shot. I plant clones into straight coir and feed them at the rate I mentioned from when they are babies all the way to when they are ready to move into the production environment. You must water to runoff every 3 or 4 irrigations or else you risk getting a toxic buildup, as most hydroponic nutrients are not designed for nutrient retention like nutrients designed for natural soil.
For blooming cannabis, I switch to Athena Bloom + Core at 8g/gal and 5g/gal respectively, ph adjusted to a stable 5.8 (mixing to a ph of 5.5 in this case will settle to 5.8 after 12 hours of aeration in the reservoir). I've noticed that municipal water ph drifts quite a bit several hours after mixing so you must create a batch of nutrient and check it the next day or else use a device to correct the ph as it drifts before giving it to the plants. Again, you could look up people's published nutrient breakdowns of this nutrient to see how it compares with products in your area, or custom mixes.
In my opinion, what people usually attribute to calcium lockout with coir is usually really a ph issue, low quality coir with an extremely high initial potassium content, or over irrigation (constantly soggy root conditions).
All of my suggestions above are with artificial lighting with relatively high intensity and co2 enrichment; if you are growing under natural lighting I would adjust the nutrients down.
Does NSO works as a preventive method aswell?
If by NSO you mean the neem oil remaining after ethanol extraction, then yes.